Challenges

• Extreme drowning hazard; difficult river passage for non-motorized boats (including canoes and kayaks)
• Water diversion for agriculture needed to be maintained
• Large river with varying discharge and harsh ice conditions
• Project needed to span the entire width of the river
• Flooding event in 2013 damaged part of the project; some areas needed to be rebuilt

Solutions

• Pools and rapids constructed downstream of weir to increase water levels to facilitate passage and improve safety
• Two channels constructed – Low Water Channel provides bypass for novice boaters; High Water Channel provides whitewater play areas for more experienced boaters
• Divide island built between the channels, providing bird and wildlife habitat and refuge for boaters
• Fish passage enhancements including notches in existing weir to facilitate fish passage at low river flows
• Weir modifications blended with natural surroundings of the river by using natural materials such as boulders, cobbles, and gravel where possible
• Limiting impact of construction on aquatic environment was considered extensively in the design

Successes

• Increased safety and navigability
• Improved fish passage and habitat
• Develop new opportunities for recreational boating
• Increased tourism to Calgary and surrounding area
• Using boulders with concrete provided robust, cost effective structures and faster construction, resulting in less impact on aquatic environment than conventional hydraulic structures
• Multiple stakeholders involved in development of project safety plan and throughout construction and commissioning